The present invention relates to arrangements for coupling light at high efficiency between a light source and one or more light distribution harnesses, such as lenses or light guides. For instance, it is desirable to feed light into readily available light guides having numerical apertures of between 0.4 and 0.65. As used herein, a numerical aperture of 0.5 is obtained where 90 percent of the light is contained within a 60-degree cone angle. The above crossreferenced application to J. M. Davenport et al. describes and claims arrangements for efficiently coupling light from a high brightness light source, such as a xenon metal halide high pressure discharge lamp or a halogen lamp, to light guides or other distribution harnesses. In one of the embodiments disclosed, elliptical reflectors focus light through tapered rods into light guides. The tapered rods receive light at one angular distribution at their smaller ends, and transmit light at a lower angular distribution through their larger ends. This achieves a so-called angle-to-area conversion that beneficially enables the use of light guides having numerical apertures in the mentioned range.
It would, however, be desirable to provide further light coupling arrangements that employ different optical elements to achieve a reduction in angular distribution of light transmitted to a light distribution harness. It would also be desirable if embodiments of light coupling arrangements using such different optical elements could be manufactured more easily than embodiments using tapered rods.